Vehicle control device and control method

ABSTRACT

A vehicle control device includes an electronic control unit configured to: enlarge the detection range, when the electronic control unit determines that a current deceleration support control is control for passing the object; set a new target deceleration of the host vehicle when a new object with a possibility of collision with the host vehicle has been detected in the enlarged detection range; determine whether an interval from an ending time of the current deceleration support control to a starting time of the next deceleration support control is less than a threshold value, when the electronic control unit determines that the next deceleration support control is control for passing the new object; and perform one of the inter-vehicle distance control and acceleration support control from the ending time to the starting time, when the electronic control unit determines that the interval is less than the threshold value.

INCORPORATION BY REFERENCE

This application is a continuation of U.S. patent application Ser. No.16/908,130 filed Jun. 22, 2020, which is a continuation of U.S. patentapplication Ser. No. 16/055,638, filed Aug. 6, 2018 (now U.S. Pat. No.10,723,349 issued Jul. 28, 2020), which claims priority based onJapanese Patent Application No. 2017-166943, filed on Aug. 31, 2017. Theentire disclosures of the prior applications are considered part of thedisclosure of the accompanying continuation application, and are herebyincorporated by reference.

BACKGROUND 1. Technical Field

The disclosure relates to a vehicle control device and a control methodand more particularly to a vehicle control device and a control methodwhich reduce collision with an obstacle.

2. Description of Related Art

Japanese Unexamined Patent Application Publication No. 2015-155295 (JP2015-155295 A) discloses a vehicle control device that performs vehiclespeed control when a vehicle passes a pedestrian. The vehicle controldevice identifies a pedestrian near the vehicle using an onboard sensor.The vehicle control device calculates a probability of collision withthe identified pedestrian and compares the calculated probability with athreshold value. When the probability of collision is higher than thethreshold value, the vehicle control device sets a separation distancefrom the identified pedestrian in a current traveling lane. The vehiclecontrol device determines whether a traveling speed of the vehicle ishigher than an upper-limit speed at which the set separation distancecan be used. The vehicle speed control is control for generating abraking force in the vehicle before passing the identified pedestrianand decelerating the vehicle to a target speed when the traveling speedof the vehicle is higher than the upper-limit speed. According to thisvehicle speed control, it is possible to avoid collision with theidentified pedestrian and to safely pass the pedestrian.

SUMMARY

JP 2015-155295 A mentions that the vehicle returns to the travelingspeed before passing the identified pedestrian after passing has beencompleted. Although details thereof are not mentioned in JP 2015-155295A, it is generally necessary to accelerate the vehicle in order toreturn to the traveling speed before passing. In order to accelerate thevehicle, it is assumed that it is necessary to decrease a braking forceapplied to the vehicle for deceleration and to generate a driving forcein the vehicle or to increase a driving force already applied to thevehicle. Such automatic vehicle speed control in which an action of thebraking force for a decelerating operation and an action of the drivingforce for an accelerating operation thereafter are combined is alsorepeatedly performed after the vehicle has returned to the travelingspeed before passing.

Here, there is a problem in that the vehicle control device may notidentify a new pedestrian who will be passed by the vehicle duringexecution of automatic vehicle speed control. This is because a range inwhich the vehicle controller can identify a pedestrian which will bepassed is normally set to be constant. In this case, there is apossibility that an accelerating operation will be quickly switched to adecelerating operation when the vehicle control device barely identifiesa new pedestrian during acceleration after passing the previouslyidentified pedestrian. Alternatively, when the vehicle control devicebarely identifies a new pedestrian after returning to the travelingspeed before passing, a decelerating operation may be started with nomargin from ending of an accelerating operation. In either case, thereis a likelihood that a driver will feel discomfort in an automaticvehicle speed control sequence.

There is another problem in that a driver may notice a new pedestrianduring execution of automatic vehicle speed control but the vehiclecontrol device may not identify the new pedestrian. In this case, sincethe vehicle control device cannot identify the new pedestrian, there isa likelihood that the driver will feel discomfort that an acceleratingoperation can be started after passing the previously identifiedpedestrian.

The disclosure provides a technique of reducing discomfort which is feltby a driver during execution of automatic vehicle speed control in avehicle control device and a control method in which automatic vehiclespeed control for avoiding collision with an obstacle with a possibilityof collision with a vehicle is performed.

An exemplary aspect of the prevent disclosure is a vehicle controldevice. The vehicle control device is configured to execute decelerationsupport control during execution of inter-vehicle distance control orconstant speed control. The deceleration support control is control foravoiding collision with an object with a possibility of collision with ahost vehicle. The vehicle control device includes an electronic controlunit configured to: set a target deceleration of the host vehicle duringexecution of the deceleration support control when the object has beendetected in a detection range; determine whether current decelerationsupport control based on the target deceleration is control for passingthe object; enlarge the detection range during execution of the currentdeceleration support control, when the electronic control unitdetermines that the current deceleration support control is control forpassing the object; set a new target deceleration of the host vehicleduring execution of next deceleration support control for avoidingcollision with a new object when a new object with a possibility ofcollision with the host vehicle has been detected in the enlargeddetection range during execution of the current deceleration supportcontrol; determine whether the next deceleration support control iscontrol for passing the new object; determine whether an interval froman ending time of the current deceleration support control to a startingtime of the next deceleration support control is less than a thresholdvalue, when the electronic control unit determines that the nextdeceleration support control is control for passing the new object; andperform one of the inter-vehicle distance control and accelerationsupport control from the ending time to the starting time, when theelectronic control unit determines that the interval is less than thethreshold value. The acceleration support control is control based on atarget acceleration less than a target acceleration of the host vehiclewhich is set when the constant speed control is restarted. An exemplaryaspect of the prevent disclosure is a control method for a vehicle. Thevehicle is configured to execute deceleration support control duringexecution of inter-vehicle distance control or constant speed control.The deceleration support control is control for avoiding collision withan object with a possibility of collision with a host vehicle. Thevehicle includes an electronic control unit. The control methodincludes: setting, by the electronic control unit, a target decelerationof the host vehicle during execution of the deceleration support controlwhen the object has been detected in a detection range; determining, bythe electronic control unit, whether current deceleration supportcontrol based on the target deceleration is control for passing theobject; enlarging, by the electronic control unit, the detection rangeduring execution of the current deceleration support control, when theelectronic control unit determines that the current deceleration supportcontrol is control for passing the object; setting, by the electroniccontrol unit, a new target deceleration of the host vehicle duringexecution of next deceleration support control for avoiding collisionwith a new object, when a new object with a possibility of collisionwith the host vehicle has been detected in the enlarged detection rangeduring execution of the current deceleration support control;determining, by the electronic control unit, whether the nextdeceleration support control is control for passing the new object;determining, by the electronic control unit, whether an interval from anending time of the current deceleration support control to a startingtime of the next deceleration support control is less than a thresholdvalue, when the electronic control unit determines that the nextdeceleration support control is control for passing the new object; andperforming, by the electronic control unit, one of the inter-vehicledistance control and acceleration support control from the ending timeto the starting time when the electronic control unit determines thatthe interval is less than the threshold value. The acceleration supportcontrol is control based on a target acceleration less than a targetacceleration of the host vehicle which is set when the constant speedcontrol is restarted.

According to the disclosure, when it is determined that the currentdeceleration support control is control for passing a decelerationobject, the detection range is enlarged during execution of the currentdeceleration support control and thus it is possible to increase anopportunity to recognizing a new deceleration object during execution ofthe current deceleration support control. In a case in which a newdeceleration object is recognized during enlargement of the detectionrange, when the next deceleration support control for avoiding collisionwith the new deceleration object is control for passing the newdeceleration object and the interval from the ending time of the currentdeceleration support control to the starting time of the nextdeceleration support control is short, acceleration control isperformed. Accordingly, it is possible to reduce discomfort which isfelt by a driver during a support control sequence from starting of thecurrent deceleration support control to ending of the next decelerationsupport control.

The threshold value may be a value which is set based on a vehicle speedat an ending time of the current deceleration support control.

BRIEF DESCRIPTION OF THE DRAWINGS

Features, advantages, and technical and industrial significance ofexemplary embodiments of the disclosure will be described below withreference to the accompanying drawings, in which like numerals denotelike elements, and wherein:

FIG. 1 is a diagram illustrating a configuration of a vehicle controldevice according to an embodiment of the disclosure;

FIG. 2 is a diagram illustrating an operation example of a host vehiclewhen deceleration support control is performed by interruption duringexecution of constant speed control;

FIG. 3 is a diagram illustrating an operation example of the hostvehicle when a new deceleration object has been recognized after thedeceleration support control illustrated in FIG. 2 has been completed;

FIG. 4 is a diagram illustrating an example of support control accordingto the embodiment of the disclosure;

FIG. 5 is a diagram illustrating an example of a support controlprocessing routine which is performed by a driving support ECU accordingto the embodiment of the disclosure;

FIG. 6 is a diagram illustrating an example of a support controlprocessing routine which is performed by the driving support ECUaccording to the embodiment of the disclosure;

FIG. 7 is a diagram illustrating an example of a support controlprocessing routine which is performed by the driving support ECUaccording to the embodiment of the disclosure;

FIG. 8 is a diagram illustrating an example of support control accordingto a modified example of the embodiment of the disclosure; and

FIG. 9 is a diagram illustrating an example of a processing routinewhich is performed by a driving support ECU to realize the supportcontrol according to the modified example of the embodiment of thedisclosure illustrated in FIG. 8 .

DETAILED DESCRIPTION OF EMBODIMENTS

Hereinafter, an embodiment of the disclosure will be described withreference to the accompanying drawings. Common elements in the drawingswill be referred to by the same reference signs and description thereofwill not be repeated. The disclosure is not limited by the followingembodiment.

FIG. 1 is a diagram illustrating a configuration of a vehicle controldevice according to an embodiment of the disclosure. The vehicle controldevice according to this embodiment includes a driving support ECU 10,an engine ECU 20, a brake ECU 30, and a warning ECU 40. Each ECUincludes a microcomputer as a major element and they are connected toeach other such that the ECUs can transmit and receive information via acontroller area network (CAN) which is not illustrated. ECU is anabbreviation for electric control unit. In this specification, themicrocomputer includes a CPU and a storage device such as a ROM and aRAM, and the CPU embodies various functions by executing an instruction(a program) stored in the ROM. In this specification, a vehicle in whichthe vehicle control device is mounted is also referred to as a “hostvehicle.”

The driving support ECU 10 is connected to an external sensor 51, avehicle speed sensor 52, a yaw rate sensor 53, an acceleration sensor54, an accelerator pedal sensor 55, a brake pedal sensor 56, variousengine sensors 57, and an operation switch 58. The vehicle speed sensor52, the yaw rate sensor 53, the acceleration sensor 54, the acceleratorpedal sensor 55, the brake pedal sensor 56, and various engine sensors57 are classified as internal sensors.

The external sensor 51 has a function of acquiring at least informationon a road in front of the host vehicle and a three-dimensional objectnear the road. Examples of a three-dimensional object include a mobileobject such as a pedestrian, a bicycle, or an automobile and astationary object such as a power pole, a tree, or a guard rail.

The external sensor 51 includes, for example, a radar sensor and acamera sensor. The radar sensor radiates, for example, radio waves of amillimeter wave band (hereinafter also referred to as “millimeter radiowaves”) to the surroundings (including at least the front) of the hostvehicle. When a three-dimensional object that reflects the millimeterradio waves is present in a radiation range, the radar sensor calculatespresence of a three-dimensional object and a relative relationshipbetween the host vehicle and the three-dimensional object (such as adistance between the host vehicle and the three-dimensional object and arelative speed of the host vehicle with respect to the three-dimensionalobject) using the reflected radio waves. The camera sensor includes, forexample, a stereoscopic camera. The camera sensor images a left sceneand a right scene of the front of the vehicle and calculates the shapeof a road, the presence of a three-dimensional object, the relativerelationship between the host vehicle and the three-dimensional object,and the like based on data of the captured right and left images. Thecamera sensor recognizes lane markers (hereinafter also referred to as“white lines”) such as outside lines of a road, a center line of a road,and a boundary line between a traveling lane and a passing lane, andcalculates the shape of the road and the positional relationship betweenthe road and the host vehicle.

Information acquired by the external sensor 51 is also referred to as“target information.” The external sensor 51 repeatedly transmits thetarget information to the driving support ECU 10 at predeterminedintervals. The external sensor 51 does not have to include the radarsensor and the camera sensor, and may include, for example, only thecamera sensor. Information of a navigation system may be used asinformation on the shape of a road on which the host vehicle travels andinformation indicating the positional relationship between the road andthe host vehicle.

The vehicle speed sensor 52 detects a traveling speed of the hostvehicle (hereinafter also referred to as a “vehicle speed”) andtransmits a detection signal thereof to the driving support ECU 10. Theyaw rate sensor 53 detects a yaw rate acting on the host vehicle andtransmits a detection signal thereof to the driving support ECU 10. Theacceleration sensor 54 detects a longitudinal acceleration which is anacceleration acting to the front and rear sides of the host vehicle anda lateral acceleration which is an acceleration acting to the right-leftdirection (a vehicle width direction) of the host vehicle, and transmitsdetection signals thereof to the driving support ECU 10. The vehiclespeed sensor 52 may be a wheel speed sensor. The accelerator pedalsensor 55 detects an amount of depression of an accelerator pedal of thehost vehicle and transmits a detection signal thereof to the drivingsupport ECU 10. The brake pedal sensor 56 detects an amount ofdepression of a brake pedal of the host vehicle and transmits adetection signal thereof to the driving support ECU 10. The variousengine sensors 57 detect an operating state quantity of a spark ignitionengine which is a drive source of the host vehicle. The various enginesensors 57 include a throttle valve opening sensor, an engine rotationspeed sensor, and an intake air sensor.

The operation switch 58 is a selection operator that can be used for adriver to select a control mode which is performed by the drivingsupport ECU 10. An operating mode in which inter-vehicle distancecontrol and constant speed control which will be described later areperformed and a non-operating mode in which such control is notperformed can be selected as the control mode.

The engine ECU 20 is connected to an engine actuator 21. The engineactuator 21 includes a throttle valve actuator and an actuator of a fuelinjection valve or the like. When the engine actuator 21 is driven, adriving force corresponding to a torque generated from the engine 22 istransmitted to vehicle wheels. The engine ECU 20 drives the throttlevalve actuator such that a degree of opening of the throttle valvematches a set target degree of opening. The engine ECU 20 determines thetarget degree of opening such that it increases as an amount ofdepression of the accelerator pedal increases at the time of normaloperation.

The brake ECU 30 is connected to a brake actuator 31. The brake actuator31 is provided in a hydraulic circuit between a master cylinder (notillustrated) that pressurizes a hydraulic oil by a depressing force onthe brake pedal and frictional brake mechanisms 32 that are provided infour wheels. Each frictional brake mechanism 32 includes a brake disc 32a that is fixed to the corresponding wheel and a brake caliper 32 b thatis fixed to a vehicle body. The frictional brake mechanism 32 presses abrake pad against the brake disc 32 a to generate a frictional brakingforce by operating a wheel cylinder built in the corresponding brakecaliper 32 b by a hydraulic pressure of the hydraulic oil supplied fromthe brake actuator 31.

The warning ECU 40 is connected a human-machine interface (HMI) 41. TheHMI 41 includes, for example, voice output means such as a buzzer and aspeaker and display means such as a head-up display (HUD), a display ofa navigation system, and a combination meter. The warning ECU 40 outputswarning voice sound from the voice output means in accordance to anattention attraction command from the driving support ECU 10 or displaysa warning message or a warning lamp on the display means to inform thedriver of an operating state of support control.

The driving support ECU 10 will be described below. The driving supportECU 10 includes a vehicle course determining unit 11, athree-dimensional object detecting unit 12, a deceleration objectrecognizing unit 13, a support control determining unit 14, a supportcontrol unit 15, and a detection range setting unit 16.

The vehicle course determining unit 11 generates information on a roadon which the host vehicle will travel from now on based on the targetinformation transmitted from the external sensor 51 at eachpredetermined calculation cycle. For example, the vehicle coursedetermining unit 11 generates coordinate information (positioninformation) of a ground surface, a three-dimensional object, and whitelines using a coordinate system which has a central position of thefront end of the host vehicle as an origin and which is expanded to theright, left, and forward sides from the origin. Accordingly, the vehiclecourse determining unit 11 ascertains the shape of a traveling lane ofthe host vehicle which is defined by right and left white lines, aposition and a direction of the host vehicle in the traveling lane, anda relative position of the three-dimensional object with respect to thehost vehicle. The vehicle course determining unit 11 calculates aturning radius of the host vehicle based on the yaw rate detected by theyaw rate sensor 53 and the vehicle speed detected by the vehicle speedsensor 52, and calculates a track of the host vehicle based on theturning radius.

The three-dimensional object detecting unit 12 determines whether athree-dimensional object is a mobile object or a stationary object basedon change of a position of the three-dimensional object which is presentin a detection range set by the detection range setting unit 16. Whenthe three-dimensional object is determined to be a mobile object, thethree-dimensional object detecting unit 12 calculates a track of thethree-dimensional object. For example, a moving speed in thelongitudinal direction (the traveling direction of the host vehicle) ofthe three-dimensional object can be calculated from a relationshipbetween the vehicle speed and the relative speed with respect to thethree-dimensional object. A moving speed in the lateral direction of thethree-dimensional object can be calculated from change of a distancebetween a lateral end position of the three-dimensional object and thewhite line detected by the external sensor 51. The three-dimensionalobject detecting unit 12 calculates the track of the three-dimensionalobject based on the moving speeds in the longitudinal direction and thelateral direction of the three-dimensional object. The three-dimensionalobject detecting unit 12 may calculate the track of thethree-dimensional object based on the calculated track of the hostvehicle and the distance between the host vehicle and thethree-dimensional object detected by the external sensor 51.

The deceleration object recognizing unit 13 determines a possibilitythat the host vehicle will collide with the three-dimensional object(hereinafter also referred to as a “possibility of collision”) when thehost vehicle travels while maintaining the current traveling state basedon the position of the three-dimensional object and the track of thehost vehicle. When the three-dimensional object is a mobile object, thetrack of the three-dimensional object is calculated and the possibilityof collision is determined based on the track of the three-dimensionalobject and the track of the host vehicle. The deceleration objectrecognizing unit 13 calculates a predicted collision time (TTC: Time ToCollision) which is a predicted time until the host vehicle collideswith the three-dimensional object (a remaining time up to collision)using Equation (1) based on the distance L₁ between thethree-dimensional object and the host vehicle and the relative speed Vr₁with respect to the three-dimensional object.TTC=L ₁ /Vr ₁  (1)

When the predicted collision time TTC is equal to or less than a presetcollision determination value TTC₁, the deceleration object recognizingunit 13 determines that there is a possibility of collision. When thepredicted collision time TTC is greater than a preset collisiondetermination value TTC₂ (>TTC₁), the deceleration object recognizingunit 13 determines that there is no possibility of collision. When thepredicted collision time TTC is between the collision determinationvalue TTC₁ and the collision determination value TTC₂, the decelerationobject recognizing unit 13 determines that there is a low possibility ofcollision. When it is determined that the possibility of collision ishigh and it is determined that the possibility of collision is low, thedeceleration object recognizing unit 13 recognizes the three-dimensionalobject as a deceleration object (an object). That is, the decelerationobject recognizing unit 13 recognizes the three-dimensional object as adeceleration object when the predicted collision time TTC is equal to orless than the collision determination value TTC₂.

The support control determining unit 14 determines whether the controlmode has been set by the operation switch 58. When the operating modehas been selected, the support control determining unit 14 selects oneof the inter-vehicle distance control and the constant speed controldepending on whether there is a preceding vehicle which travels in frontof the host vehicle. The inter-vehicle distance control is control forcausing the host vehicle to follow a preceding vehicle while maintaininga target inter-vehicle distance when there is a preceding vehicle. Theconstant speed control is control for causing the host vehicle to travelwhile maintain a target vehicle speed when there is no precedingvehicle.

When the support control determining unit 14 has selected the constantspeed control, the support control unit 15 sets a target acceleration ora target deceleration of the host vehicle, for example, based on apreset target vehicle speed, a vehicle speed of the host vehicle, and aroad surface gradient of a currently traveling lane. When the supportcontrol determining unit 14 has selected the inter-vehicle distancecontrol, the support control unit 15 sets a target acceleration or atarget deceleration of the host vehicle, for example, based on aninter-vehicle distance between the preceding vehicle and the hostvehicle, a relative speed with respect to the preceding vehicle, and theroad surface gradient of the currently traveling lane.

When the target acceleration in the constant speed control or theinter-vehicle distance control has been set, the support control unit 15transmits a driving command indicating the target acceleration to theengine ECU 20. The engine ECU 20 controls the engine actuator 21 inaccordance with the target acceleration such that the engine 22 isdriven, and thus a driving force corresponding to an engine torque isgenerated to accelerate the host vehicle. When the target decelerationin the constant speed control and the inter-vehicle distance control hasbeen set, the support control unit 15 transmits a braking commandindicating the target deceleration to the brake ECU 30. The brake ECU 30controls the brake actuator 31 in accordance with the targetdeceleration such that a frictional braking force is generated in thevehicle wheels. Accordingly, the automatic brake operates to deceleratethe host vehicle. The inter-vehicle distance control and the constantspeed control are known and thus more description thereof will not berepeated.

The support control determining unit 14 determines whether adeceleration object has been recognized by the deceleration objectrecognizing unit 13 in addition to determination of whether the controlmode has been set. When a deceleration object has been recognized, thesupport control determining unit 14 sets a starting time and/or anending time of deceleration support control for avoiding collision withthe deceleration object. The starting time and/or the ending time areset to stop the host vehicle before the deceleration object when thereis a high possibility of collision. That is, when there is a highpossibility of collision, the support control determining unit 14 setsonly the starting time.

When the operating mode has been selected, the support controldetermining unit 14 performs the support control determining unit 14 byinterrupting the inter-vehicle distance control or the constant speedcontrol by setting at least the starting time of the decelerationsupport control. When the non-operating mode has been selected, thesupport control determining unit 14 performs the deceleration supportcontrol by interrupting a driving operation of a driver by setting atleast the starting time of the deceleration support control.

When the starting time and/or the ending time of the decelerationsupport control has been set, the support control unit 15 calculates atarget deceleration for decelerating the host vehicle. For example, in acase in which the deceleration object stops, when the vehicle speed(=relative speed) at the current time is defined as V, the decelerationof the host vehicle is defined as a, and the time up to stopping of thehost vehicle is defined as t, a traveling distance X of the host vehicleuntil stopping can be expressed by Equation (2).X=V·t+(½)·a·t ²  (2)The time t until the vehicle stops can be expressed by Equation (3).T=−V/a  (3)

Accordingly, by substituting Equation (3) into Equation (2), thedeceleration a which is required for stopping the host vehicle at thetraveling distance TD can be expressed by Equation (4).A=−V2/2TD  (4)

In order to stop the host vehicle a distance β before the decelerationobject, the traveling distance TD can be set to a distance (L₁-β)obtained by subtracting the distance β from the distance L₁ detected bythe external sensor 51. When the deceleration object is moving, thedeceleration a can be calculated using the relative speed with respectto the deceleration object.

The support control unit 15 sets the calculated deceleration a as thetarget deceleration. Here, the deceleration which can be generated inthe host vehicle is limited (for example, about −1G). Accordingly, whenthe absolute value of the calculated target deceleration is greater thanthe absolute value of an upper limit value amax, the support controlunit 15 sets the target deceleration to the upper limit value amax. Thesupport control unit 15 transmits a braking command indicating thetarget deceleration to the brake ECU 30. Accordingly, the brake ECU 30controls the brake actuator 31 in accordance with the targetdeceleration such that a frictional braking force is generated in thevehicle wheels. Accordingly, the automatic brake operates to deceleratethe host vehicle.

The support control determining unit 14 transmits an attentionattraction command to the warning ECU 40 in a step before the automaticbrake operates. Accordingly, the warning ECU 40 rings the voice outputmeans or displays a warning message or a warning lamp on the displaymeans to inform the driver of the operating state of the decelerationsupport control.

The detection range setting unit 16 sets a detection range in which adeceleration object is detected. The detection range is defined by alongitudinal width and a lateral width of the front of the host vehiclealong the currently traveling lane. The longitudinal width is set to,for example, a value α·V obtained by multiplying the vehicle speed V atthe current time by a coefficient α. The lateral width is set to, forexample, a value W·γ+ε obtained by adding a margin ε on an opposing laneside to a value W·γ acquired by multiplying the vehicle width W of thehost vehicle by a coefficient γ. The coefficient α, the coefficient γ,and the margin ε are set in advance depending on a degree of safetyrequired for the host vehicle. The coefficient α is greater than thecollision determination value TTC₂ and the coefficient γ is greaterthan 1. The longitudinal width and the lateral width may be set to fixedvalues.

Details of the support control determining unit 14 will be describedbelow. As described above, when a deceleration object has beenrecognized, the support control determining unit 14 sets the startingtime and/or the ending time of the deceleration support control andperforms the deceleration support control. When the constant speedcontrol or the inter-vehicle distance control is being performed, thesupport control determining unit 14 interrupts the support control underexecution and performs the deceleration support control.

FIG. 2 is a diagram illustrating an operation example of the hostvehicle when the deceleration support control interrupts the constantspeed control under execution. In the example illustrated in FIG. 2 , adeceleration object RS is recognized in the detection range DR. Theposition of the deceleration object RS is in the opposing lane with thecenter line CL interposed therebetween, and the direction relative tothe host vehicle VC is right. In the example illustrated in FIG. 2 , itis assumed that it is determined that there is a low possibility ofcollision of the host vehicle VC with the deceleration object RS. It isalso assumed that a target deceleration for passing the decelerationobject RS in a decelerated state is set instead of stopping the hostvehicle VC before the deceleration object RS.

Here, when the non-operating mode has been selected (that is, when theconstant speed control or the inter-vehicle distance control is notperformed) and the starting time t₁ of the deceleration support controlis too early, the operation of the automatic brake interferes with thedriver's operation of the brake pedal. For example, even when the drivernotices presence of the deceleration object RS and attempts to operatethe brake pedal when the deceleration object RS and the host vehicle VCapproach each other, the automatic brake may operate earlier than theoperation of the brake pedal. In this case, there is concern that thedriver will feel discomfort. In order to avoid this inconvenience, thesupport control determining unit 14 sets a time at which the hostvehicle VC is predicted to approach the deceleration object RS as thestarting time t₁ when the non-operating mode has been selected. When theoperating mode has been selected, similarly, the support controldetermining unit 14 sets such a time as the starting time t₁.

The support control determining unit 14 sets a time at which the hostvehicle VC is predicted to fully pass the deceleration object RS as theending time t₂ of the deceleration support control. The time at whichthe host vehicle is predicted to fully pass the deceleration object RSis calculated by adding an execution time TA of the deceleration supportcontrol to the starting time t1. The execution time TA can be expressedby Equation (5) using a distance L₂ between the deceleration object RSand the host vehicle VC at the starting time of the deceleration supportcontrol, the longitudinal width WRS of the deceleration object RS, andthe relative speed Vr₂ with respect to the deceleration object RS.TA=(L ₂ +WRS)/Vr ₂  (5)

Change of the vehicle speed when the deceleration support controlinterrupts the constant speed control is illustrated in an upper part ofFIG. 2 . Before the starting time t₁, the constant speed control isexecuted and the vehicle speed is maintained constant. After thestarting time t₁, the deceleration support control is preferentiallyexecuted and thus the vehicle speed decreases slowly. After the endingtime t₂, the vehicle speed increases with restarting of the constantspeed control. After the time t₃, the vehicle speed is recovered to thesame vehicle speed as before the starting time t₁.

Determination of a three-dimensional object by the three-dimensionalobject detecting unit 12 and determination of a possibility of collisionby the deceleration object recognizing unit 13 are performed at eachpredetermined calculation cycle. Accordingly, when a new decelerationobject is recognized from the starting time to the ending time of thedeceleration support control, the support control determining unit 14sets a starting time and/or an ending time of new deceleration supportcontrol for avoiding collision with the new deceleration object.Conversely, when a new deceleration object is not recognized duringexecution of the deceleration support control, the deceleration supportcontrol ends as scheduled.

When a new deceleration object is recognized after the decelerationsupport control ends, the support control determining unit 14 sets astarting time and/or an ending time of new deceleration support controlfor avoiding collision with the new deceleration object. FIG. 3 is adiagram illustrating an operation example of the host vehicle when a newdeceleration object is recognized after the deceleration support controldescribed above with reference to FIG. 2 has ended. In the exampleillustrated in FIG. 3 , deceleration support control for avoidingcollision with a deceleration object RS₁ is executed by interrupting theconstant speed control. In the example illustrated in FIG. 3 , a newdeceleration object RS₂ is recognized in the detection range DR afterthe deceleration support control has ended. The position of thedeceleration object RS₂ is in the opposing lane with the center line CLinterposed therebetween and the direction thereof relative to the hostvehicle VC is right.

In the example illustrated in FIG. 3 , it is assumed that it isdetermined that there is a low possibility of collision of the hostvehicle VC with the deceleration object RS₂. It is also assumed that atarget deceleration for passing the deceleration object RS₂ in adecelerated state is set instead of stopping the host vehicle VC beforethe deceleration object RS₂. Then, next deceleration support control foravoiding collision with the deceleration object RS₂ is started with nomargin from ending of the current deceleration support control foravoiding collision with the deceleration object RS₁.

A time at which the host vehicle VC is predicted to approach thedeceleration object RS₂ is set as a starting time t₁ of the nextdeceleration support control. It is assumed that an interval from theending time t₂ to the starting time t₁ is short. Then, a sequence ofvehicle operations including a decelerating operation accompanying thecurrent deceleration support control after the starting time t₁, anaccelerating operation accompanying restart of the constant speedcontrol after the ending time t₂, and a decelerating operationaccompanying the next deceleration support control after the startingtime t₄ provides a complicated feeling to the driver.

Since the deceleration object RS₂ is barely recognized after the endingtime t₂, another problem is caused when the driver notices presence ofthe deceleration object RS₂ before the ending time t₂. That is, thedriver may feel discomfort that an accelerating operation is startedafter the ending time t₂ because the host vehicle VC cannot identify thedeceleration object RS₂.

In consideration of such a problem, in this embodiment, when thedeceleration support control is executed to by interrupting the constantspeed control or the inter-vehicle distance control and a braking forcefor passing the deceleration object is generated in the host vehicle,the detection range which is set by the detection range setting unit 16is enlarged from the starting time of the deceleration support controlto the ending time thereof. FIG. 4 is a diagram illustrating an exampleof support control according to the embodiment of the disclosure. In theexample illustrated in FIG. 4 , similarly to the example illustrated inFIG. 3 , the deceleration support control for avoiding collision withthe deceleration object RS₁ is executed by interrupting the constantspeed control.

In the example illustrated in FIG. 4 , the detection range DR isenlarged to the front side and the lateral sides of the host vehicle VCalong the current traveling lane. The longitudinal width of the enlargeddetection range EDR is set to, for example, a value δ·α·V obtained bymultiplying the value of the longitudinal width before enlargement by acoefficient δ. The lateral width of the enlarged detection range EDR isset to, for example, a value ζ+ε+W·γ obtained by adding an enlargedwidth ζ in the lateral direction to the value ε+W·γ of the lateral widthbefore enlargement. The coefficient δ is greater than 1.

In the example illustrated in FIG. 4 , a candidate for a newdeceleration object RSC is detected in the detection range EDR.Accordingly, the driving support ECU 10 performs the same process aswhen the deceleration object RS₁ is recognized on the candidate RSC. Theprocess on the candidate RSC is performed based on scheduled positionsof the candidate RSC and the host vehicle VC at the ending time of thedeceleration support control (that is, the ending time t₂) and therelative speed with respect to the candidate RSC at the ending time whenthe deceleration support control for avoiding collision with thedeceleration object RS₁ is executed as scheduled, instead of thepositions of the candidate RSC and the host vehicle VC at a time t₅ atwhich the candidate RSC is detected.

Specifically, the deceleration object recognizing unit 13 predictivelydetermines a possibility of collision of the host vehicle VC with thecandidate RSC based on the ending time t₂. First, the decelerationobject recognizing unit 13 calculates the predicted collision time TTCuntil the host vehicle VC collides with the candidate RSC using Equation(1). The distance L₁ in Equation (1) is replaced with a distance betweenthe candidate RSC and the host vehicle VC at the ending time t₂. Therelative speed Vr₁ in Equation (1) is replaced with the relative speedwith respect to the candidate RSC at the ending time t₂. Subsequently,the deceleration object recognizing unit 13 determines whether thecandidate RSC corresponds to a new deceleration object by comparing thecalculated predicted collision time TTC with the collision determinationvalues TTC₁ and TTC₂.

In the example illustrated in FIG. 4 , it is assumed that the candidateRSC has been recognized as a new deceleration object RS₃. In this case,the support control determining unit 14 sets a starting time and/or anending time of next deceleration support control for avoiding collisionwith the deceleration object RS₃ similarly to the case in which thedeceleration object RS₁ is recognized. The position of the decelerationobject RS₃ is in the opposing lane with the center line CL interposedtherebetween, and the direction of the deceleration object RS₃ relativeto the host vehicle VC is the same direction (right) as the relativedirection with respect to the deceleration object RS₁. In the exampleillustrated in FIG. 4 , it is assumed that it is determined that thereis a low possibility of collision of the host vehicle VC with thedeceleration object RS₃. It is also assumed that a target decelerationfor passing the deceleration object RS₃ in a decelerated state is setinstead of stopping the host vehicle VC before the deceleration objectRS₃.

A time at which the host vehicle VC is predicted to approach thedeceleration object RS₃ is set as a starting time to of the nextdeceleration support control. It is assumed that an interval from theending time t₂ to the starting time to is short. Then, the same problemas the problem described with reference to FIG. 3 is caused. Therefore,the support control determining unit 14 sets a starting time and anending time of control (hereinafter also referred to as “intermediatesupport control”) which interrupts the constant speed control from theending time t₂ to the starting time to. The starting time of theintermediate support control is a time matching the ending time t₂. Theending time of the intermediate support control is a time matching thestarting time t₆.

When the starting time and the ending time of the intermediate supportcontrol have been set, the support control unit 15 sets a targetacceleration which can maintain the vehicle speed at the ending time t₂during execution of the intermediate support control. The supportcontrol unit 15 sets the target acceleration based on the vehicle speedat the ending time t₂ and the road surface gradient. The support controlunit 15 transmits a driving command indicating the set targetacceleration to the engine ECU 20.

Change of the vehicle speed when the intermediate support controlinterrupts the constant speed control is illustrated in an upper part ofFIG. 4 . The change of the vehicle speed until the ending time t₂ is thesame as described above with reference to FIG. 2 . In the exampleillustrated in FIG. 4 , since the intermediate support control isexecuted from the ending time t₂ to the starting time t₆, the previousvehicle speed is maintained at the vehicle speed at the ending time t₂.After the starting time to, since the deceleration support control ispreferentially executed, the vehicle speed decreases slowly.

FIGS. 5 to 7 are diagrams illustrating an example of a support controlprocessing routine which is performed by the driving support ECU 10according to the embodiment of the disclosure. This processing routineis repeatedly performed at each calculation cycle in a period in whichan ignition switch is in an ON state.

When the processing routine illustrated in FIGS. 5 to 7 is started, thedriving support ECU 10 first determines whether a deceleration objecthas been recognized (Step S10). The process of recognizing adeceleration object is the same as described above in description of thedeceleration object recognizing unit 13. When it is determined that adeceleration object has not been recognized, the driving support ECU 10ends this processing routine.

When it is determined in Step S10 that a deceleration object has beenrecognized, the driving support ECU 10 sets a starting time and/or anending time of deceleration support control (Step S12). The process ofsetting the starting time and the like of the deceleration supportcontrol is the same as described in description of the support controldetermining unit 14.

Subsequent to Step S12, the driving support ECU 10 sets a targetdeceleration (Step S14). The process of setting a target deceleration isthe same as described in description of the support control unit 15.Then, the driving support ECU 10 transmits a braking command to thebrake ECU 30 (Step S16) such that the deceleration support control isstarted from the starting time set in Step S12.

Subsequent to Step S16, the driving support ECU 10 determines whether apossibility of collision with the deceleration object is high (StepS18). Whether the possibility of collision with the deceleration objectis high is determined depending on whether the predicted collision timeTTC is equal to or less than the collision determination value TTC₁. Asa result, when it is determined that the possibility of collision withthe deceleration object is high, the current deceleration supportcontrol can be determined to be control for stopping the host vehiclebefore the deceleration object. Accordingly, the driving support ECU 10ends this processing routine.

When it is determined in Step S18 that the possibility of collision withthe deceleration object is not high, the driving support ECU 10determines whether the operating mode has been selected (Step S20). Whenit is determined that the operating mode has not been selected, it canbe determined that the inter-vehicle distance control or the constantspeed control is not restarted after the deceleration support controlhas ended. Accordingly, the driving support ECU 10 ends this processingroutine.

When it is determined in Step S20 that the operating mode has beenselected, the driving support ECU 10 determines whether the startingtime of the deceleration support control has arrived (Step S22). Thedetermination process of Step S22 is repeatedly performed until thedetermination result is positive. When the determination result ispositive, that is, when it is determined that the starting time of thedeceleration support control has arrived, the driving support ECU 10enlarges the detection range (Step S24). The process of enlarging thedetection range is the same as described above with reference to FIG. 4.

Subsequent to Step S24, the driving support ECU 10 determines whetherthe ending time of the deceleration support control has arrived (StepS26). That is, the driving support ECU 10 determines whether thedeceleration support control is being executed. When it is determinedthat the ending time of the deceleration support control has arrived,the driving support ECU 10 reduces the detection range (Step S28). Thatis, the driving support ECU 10 returns the detection range enlarged inStep S24 to the original size.

When it is determined in Step S26 that the ending time of thedeceleration support control has not arrived, the driving support ECU 10determines whether a new deceleration object has been recognized (StepS30). The process of recognizing a new deceleration object is the sameas described above with reference to FIG. 4 . When it is determined thata new deceleration object has not been recognized, the driving supportECU 10 returns to the determination process of Step S26.

When it is determined in Step S30 that a new deceleration object hasbeen recognized, the driving support ECU 10 sets a starting time and/oran ending time of next deceleration support control (Step S32). Theprocess of setting the starting time and the like of the nextdeceleration support control is the same as described above withreference to FIG. 4 .

Subsequent to Step S32, the driving support ECU 10 determines whether apossibility of collision with the new deceleration object is high (StepS34). Whether the possibility of collision with the new decelerationobject is high is determined depending on whether the predictedcollision time TTC is equal to or less than the collision determinationvalue TTC₁. As a result, when it is determined that the possibility ofcollision with the new deceleration object is high, the nextdeceleration support control can be determined to be control forstopping the host vehicle before the new deceleration object.Accordingly, the driving support ECU 10 sets a target deceleration (StepS36). The process of setting a target deceleration is the same asdescribed in description of the support control unit 15.

Subsequent to Step S36, the driving support ECU 10 transmits a brakingcommand to the brake ECU 30 (Step S38) such that the decelerationsupport control is started at the starting time set in Step S32. Then,the driving support ECU 10 reduces the detection range (Step S28).

When it is determined in Step S34 that the possibility of collision withthe new deceleration object is not high, the driving support ECU 10determines whether an interval from the ending time of the currentdeceleration support control to the starting time of the nextdeceleration support control is less than a threshold value (Step S40).The threshold value is set depending on the vehicle speed at the endingtime of the current deceleration support control. When it is determinedthat the interval is equal to or greater than the threshold value, itcan be determined that the interval from the ending time of the currentdeceleration support control to the starting time of the nextdeceleration support control is long and there is no problem inrestarting the vehicle speed control or the like. Accordingly, thedriving support ECU 10 performs the processes of Step S36 and the stepssubsequent thereto.

When it is determined in Step S40 that the interval is less than thethreshold value, the driving support ECU 10 transmits a starting timeand an ending time of intermediate support control to the brake ECU 30(Step S42). The starting time and the ending time of the intermediatesupport control are the same as described above with reference to FIG. 4.

Subsequent to Step S42, the driving support ECU 10 sets a targetacceleration in the intermediate support control set in Step S42 and atarget deceleration in the next deceleration support control (Step S44).These setting processes are the same as described above with referenceto FIG. 4 .

Subsequent to Step S44, the driving support ECU 10 transmits a drivingcommand to the engine ECU 20 (Step S46) such that the vehicle speed atthe ending time of the current deceleration support control ismaintained from the starting time to the ending time, which are set inStep S42. The driving support ECU 10 also transmits a braking command tothe brake ECU 30 such that the next deceleration support control isstarted at the starting time set in Step S32 and is ended at the endingtime set at the same step.

With the above-mentioned vehicle control device according to theembodiment, the following advantages can be achieved. That is, whendeceleration support control is executed by interrupting constant speedcontrol or inter-vehicle distance control and the deceleration supportcontrol is control for causing a host vehicle to pass a decelerationobject, the detection range during execution of the deceleration supportcontrol is enlarged to the front side and the right and left sides ofthe host vehicle. Accordingly, it is possible to increase opportunitiesto recognize a new deceleration object during execution of thedeceleration support control.

When a new deceleration object has been recognized during enlargement ofthe detection range, next deceleration support control for avoidingcollision with the new deceleration object is control for causing thehost vehicle to pass the new deceleration object, and an interval fromthe ending time of the current deceleration support control to thestarting time of the next deceleration support control is short,intermediate support control is executed. Accordingly, it is possible toavoid a situation in which an accelerating operation accompanyingrestarting of the constant speed control or the inter-vehicle distancecontrol is performed.

In the above-mentioned embodiment, the vehicle control device is basedon the premise that the host vehicle includes an engine. However, thevehicle control device according to the disclosure may be applied to ahybrid vehicle including a motor in addition to the engine and may beapplied to an electric vehicle including a motor instead of the engine.When the motor is provided, a motor ECU that receives a driving commandfrom the driving support ECU can be separately provided, and an inverteras a motor driver can be controlled by the motor ECU such that the motoris driven.

In the above-mentioned embodiment, the lateral width of the detectionrange is enlarged by a margin c to the opposing lane side. However, themargin c may be provided to the road shoulder with the left white lineLL interposed therebetween, or the margin c may not be provided.

In the above-mentioned embodiment, when an interval from the ending timeof the current deceleration support control to the starting time of thenext deceleration support control is short, the intermediate supportcontrol is executed. That is, restarting of the constant speed controlor the inter-vehicle distance control is postponed and the intermediatesupport control is executed. However, restarting of the constant speedcontrol or the inter-vehicle distance control may not be postponed. Thismodified example will be described below with reference to FIGS. 8 and 9.

FIG. 8 is a diagram illustrating support control according to a modifiedexample of the embodiment of the disclosure. The preconditions of theexample illustrated in FIG. 8 are the same as the preconditions of theexample illustrated in FIG. 4 . In the example illustrated in FIG. 8 ,the support control determining unit 14 sets an upper limit value of atarget acceleration of the host vehicle VC which is set in the restartedconstant speed control. When the upper limit value is set, theacceleration in the restarted constant speed control is lower than theoriginal acceleration. Accordingly, even when the accelerating operationis performed with the constant speed control restarted in thedecelerating operation, it is possible to reduce discomfort which willbe felt by a driver.

FIG. 9 is a diagram illustrating an example of a processing routinewhich is performed by the driving support ECU 10 to realize the supportcontrol according to the modified example of the embodiment of thedisclosure described with reference to FIG. 8 . When the processingroutine illustrated in FIG. 7 is replaced with the processing routineillustrated in FIG. 9 , the support control processing routine accordingto the modified example is described. The processing routine illustratedin FIG. 9 is different from the processing routine illustrated in FIG. 7in that the process when the determination result of Step S40 ispositive.

That is, when the determination result is positive, the driving supportECU 10 sets the upper limit value of the target acceleration in therestarted constant speed control and the target deceleration in the nextdeceleration support control (Step S48). These setting processes are thesame as described above with reference to FIG. 8 . Then, the drivingsupport ECU 10 transmits a braking command to the brake ECU 30 (StepS50) such that the next deceleration support control is started at thestarting time set in Step S32 and is ended at the ending time set in thesame step.

In this way, when it is predicted that the same next decelerationsupport control as the current deceleration support control can bestarted immediately after the current deceleration support control hasbeen ended, the above-mentioned embodiment can be modified in variousforms as long as acceleration support control based on a targetacceleration lower than the target acceleration set when theinter-vehicle distance control or the constant speed control isrestarted is performed as support control which is performed from theending time of the current deceleration support control to the startingtime of the next deceleration support control.

What is claimed is:
 1. A vehicle control device configured to executedeceleration support control during execution of inter-vehicle distancecontrol or constant speed control, the vehicle control devicecomprising: an electronic control unit (ECU) configured to: set a targetdeceleration of a host vehicle during execution of the decelerationsupport control; set a new target deceleration of the host vehicleduring execution of next deceleration support control when an objectwith a possibility of collision with the host vehicle has been detectedin a detection range during execution of a current deceleration supportcontrol; determine whether the next deceleration support control iscontrol for passing the object; when the electronic control unitdetermines that the next deceleration support control is control forpassing the object, determine whether an interval from an ending time ofthe current deceleration support control to a starting time of the nextdeceleration support control is less than a threshold value; and whenthe electronic control unit determines that the interval is less thanthe threshold value, perform one of a first intermediate control and asecond intermediate control, the first intermediate control beingcontrol setting a target acceleration to a value which maintains avehicle speed at the ending time of the current deceleration supportcontrol, and the second intermediate control being control restartingthe inter-vehicle distance control or the constant speed control.
 2. Thevehicle control device according to claim 1, wherein the ECU is furtherconfigured to, when the inter-vehicle distance control or the constantspeed control is restarted after execution of deceleration supportcontrol, set the target acceleration such that the vehicle speed at theending time of the current deceleration support control is changed tobecome equal to a vehicle speed before the execution of the decelerationsupport control, wherein a second target acceleration is smaller than afirst target acceleration, wherein the first target acceleration is atarget acceleration which is set when the inter-vehicle distance controlor the constant speed control is restarted in a case that the electroniccontrol unit does not determine, during the current deceleration supportcontrol, to execute a next deceleration support control, wherein thesecond target acceleration is a target acceleration which is set whenthe inter-vehicle distance control or the constant speed control isrestarted in the second intermediate control.
 3. The vehicle controldevice according to claim 1, wherein the threshold value is a valuewhich is set based on the vehicle speed at the ending time of thecurrent deceleration support control.
 4. A control method for a vehicleconfigured to execute deceleration support control during execution ofinter-vehicle distance control or constant speed control, using anelectronic control unit (ECU), the control method comprising: setting atarget deceleration of a host vehicle during execution of thedeceleration support control; setting a new target deceleration of thehost vehicle during execution of next deceleration support control whenan object with a possibility of collision with the host vehicle has beendetected in a detection range during execution of a current decelerationsupport control; determining whether the next deceleration supportcontrol is control for passing the object; when the next decelerationsupport control is determined as control for passing the object,determining whether an interval from an ending time of the currentdeceleration support control to a starting time of the next decelerationsupport control is less than a threshold value; and when the interval isdetermined to be less than the threshold value, performing one of afirst intermediate control and a second intermediate control, the firstintermediate control being control setting a target acceleration to avalue which maintains a vehicle speed at the ending time of the currentdeceleration support control, and the second intermediate control beingcontrol restarting the inter-vehicle distance control or the constantspeed control.
 5. The control method according to claim 4, furthercomprising, when the inter-vehicle distance control or the constantspeed control is restarted after execution of deceleration supportcontrol, setting the target acceleration such that the vehicle speed atthe ending time of the current deceleration support control is changedto become equal to a vehicle speed before the execution of thedeceleration support control, wherein a second target acceleration issmaller than a first target acceleration, wherein the first targetacceleration is a target acceleration which is set when theinter-vehicle distance control or the constant speed control isrestarted in a case that, during the current deceleration supportcontrol, the determination is not to execute a next deceleration supportcontrol, wherein the second target acceleration is a target accelerationwhich is set when the inter-vehicle distance control or the constantspeed control is restarted in the second intermediate control.
 6. Thecontrol method according to claim 4, wherein the threshold value is avalue which is set based on the vehicle speed at the ending time of thecurrent deceleration support control.
 7. A non-transitorycomputer-readable medium storing a program that causes an electroniccontrol unit (ECU) to execute deceleration support control duringexecution of inter-vehicle distance control or constant speed control,the deceleration support control comprising: setting a targetdeceleration of a host vehicle during execution of the decelerationsupport control; setting a new target deceleration of the host vehicleduring execution of next deceleration support control when an objectwith a possibility of collision with the host vehicle has been detectedin a detection range during execution of a current deceleration supportcontrol; determining whether the next deceleration support control iscontrol for passing the object; when the next deceleration supportcontrol is control for passing the object, determining whether aninterval from an ending time of the current deceleration support controlto a starting time of the next deceleration support control is less thana threshold value; and when the interval is less than the thresholdvalue, performing one of a first intermediate control and a secondintermediate control, the first intermediate control being controlsetting a target acceleration to a value which maintains a vehicle speedat the ending time of the current deceleration support control, and thesecond intermediate control being control restarting the inter-vehicledistance control or the constant speed control.
 8. The non-transitorycomputer readable medium according to claim 7, further comprising, whenthe inter-vehicle distance control or the constant speed control isrestarted after execution of deceleration support control, setting thetarget acceleration such that the vehicle speed at the ending time ofthe current deceleration support control is changed to become equal to avehicle speed before the execution of the deceleration support control,wherein a second target acceleration is smaller than a first targetacceleration, wherein the first target acceleration is a targetacceleration which is set when the inter-vehicle distance control or theconstant speed control is restarted in a case that, during the currentdeceleration support control, the determination is not to execute a nextdeceleration support control, wherein the second target acceleration isa target acceleration which is set when the inter-vehicle distancecontrol or the constant speed control is restarted in the secondintermediate control.
 9. The non-transitory computer readable mediumaccording to claim 7, wherein the threshold value is a value which isset based on the vehicle speed at the ending time of the currentdeceleration support control.